The College Board released its data on 2012 SAT scores on Monday, and beneath the headlines (which tallied how much SAT scores have slipped as more and more students take the test) was a revealing picture of the influence of students’ household income on their performance.

The influence couldn’t be more decisive. The board measured household income in increments of $20,000—starting with students from households making $0 to $20,000 annually, then $20,000 to $40,000, all the way up to $160,000—then an increment of $40,000 ($160,000 to $200,000) and then a final category of more than $200,000. And SAT scores rose considerably at every step in the income scale. The poorest students, from households making less than $20,000 had a mean combined score of 1322 out of 2400; the next highest, 1397; then 1458, then 1497—all the way to a score of 1722 for students from households making more than $200,000. That’s a 400-point difference between our richest and poorest students.

These mournful numbers cast a harsh light on the practice, beloved by “educational reformers,” of measuring teacher performance chiefly, if not exclusively, by test scores. Test scores, the data make clear, reflect social class and economic standing far more than anything else. If our educational reformers were serious about raising test scores, and student aptitude, and the competence of the American workforce, they might turn their attention to alleviating poverty and lifting living standards for our downwardly mobile working and middle class. Blaming teachers for these test scores is a lot easier, of course, than reducing our record levels of economic inequality. Problem is, it does nothing to address the huge disparities in academic performance and aptitude. Unless they tackle our yawning gaps in income and wealth, our educational reformers won’t make a dent in the problems about which they profess to care.